On Sunday August 14, stephen.walton@xxxxxxxx wrote: > Hi, > > It seems like this should be a FAQ but careful google and mailing list > archive searches didn't seem to turn up anything. > > I have two machines with legacy RAID-0 arrays created with raidtools. I > have updated one to Fedora Core 4 and now use mdadm. Am I correct in > thinking I have to use "mdadm --build" every boot to access the array? > My mdadm.conf contains > > DEVICES /dev/hda1 /dev/hdb1 /dev/hdc1 > ARRAY /dev/md0 level=raid0 num-devices=3 > devices=/dev/hda1,/dev/hdb1,/dev/hdc1 > > but the array doesn't seem to come up by itself on boot. If it is a "legacy array" in that it was created with "persisent-superblock = no" then you are right. You need to use "mdadm --build" to assemble it. --assemble ONLY works with arrays that have superblocks. With --build, you need to make sure that you get the chunksize correct of course (as it isn't stored in the superblock). > > On the same lines, can this array be converted to a new style array just > by writing new superblocks, or do I have to do the > backup-reformat-restore thing? An array with superblocks is slightly smaller than the legacy array (due to the superblocks). So you cannot do a straight conversion. If you have afford to loose the last 64k-per-device of the array, then you can simply re-create it as a with-superblock array. If you are using ext2 or ext3, then you may be able to resize you filesystem down with resize2fs and then remake the array. NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
